1. Field of the invention:
This invention relates to a disinfectant composition for medical use that is suitable for disinfection of the hands.
2. Description of the prior art:
Washbasins containing an aqueous solution of a disinfectant are provided in the nursing stations of hospitals, the entrances of hospital wards, the entrance of intensive care units, and elsewhere. For disinfection of the hands, both hands are immersed in the solution. However, a number of problems have recently been pointed out with the method that uses such basins, some of which include (1) the danger that the basin itself will become a source of infection by a variety of microorganisms if the concentration of the drug falls below a certain level, (2) the appearance of drug-resistant strains of microorganisms if the same disinfectant is used for a long period of time, and (3) the danger of recontamination after immersion from hand towels and the like. For that reason, suitable bactericidal agents such as those in ethanol solution that provide disinfection with rapid drying have been investigated.
As rapid-drying disinfectant solutions, there are ethanol solutions containing chlorhexidine digluconate, ethanol solutions containing benzalkonium chloride, etc. These disinfectant solutions are prepared by the addition of 0.1-0.5% (wt/v) of chlorhexidine digluconate or benzalkonium chloride to ethanol for disinfection (Japanese Pharmacopoeia, 76.9 to 81.4% (v/v) of ethanol in water). Because these disinfectant solutions are rapid drying and have the additional bactericidal effect of ethanol, and because chlorhexidine digluconate or benzalkonium chloride are contained therein, they can be used for the disinfection of the skin before surgery, medical devices in cases of emergency, etc. However, because contact of the skin to the ethanol solvent causes denaturation of structural proteins of the skin such as keratin, injury of the skin such as irritation or roughening may occur. For that reason, such solutions are not generally used for the frequent disinfection of the hands.
The inventors of this invention thought of the possibility of preventing skin damage by the addition of an emollient that protects the skin to this kind of disinfectant solution with ethanol as its main solvent. However, it is known that the bactericidal activity of chlorhexidine digluconate and benzalkonium chloride decreases in the presence of other substances. For example, in the presence of various substances such as serum [Journal of Infectious Diseases 53, 292 (1979)], polysaccharides [J. Periodont. Res. 8, Suppl. 12, 61 (1973)], non-ionic surfactants (Medical Journal of Okayama University 91, 251 (1979)], powdered milk, dried bovine serum, fish powder, and other organic substances [J. Appl. Bacterial., 54, 243 (1983)], the bactericidal activity of these compounds decreases. Most emollients used in cosmetics and the like are non-ionic surfactants or higher alcohols, so it is likely that when they are added, the bactericidal activity of chlorhexidine digluconate and benzalkonium chloride would decrease. In this way, an disinfectant composition for medical use that is rapid-drying and has satisfactory bactericidal activity but that does not damage the skin is not presently available.